After measuring your space and deciding on the sizing of your shelves, start by cutting your boards down to the appropriate size. You'll want two pieces for the top and bottom (I recommend using 1X12 pine), then a piece for the front of the shelf (cut to match the length of the shelves) and two for the sides (which will be cut to match the depth of the shelves).
Once all of your cuts are made, use your table saw to miter the all edges of the boards except the edge that will sit against the wall. This will allow you to create shelves with no visible end grain.
Lay them all out as shown above and tape the seams together - the painter's tape will act as a clamp to hold things in place while the glue dries!
**NOTE: For further details on this process, please see the full blog post! It's a bit complicated to explain in a brief format!